571 research outputs found
Effects of Non-Local Diffusion on Structural MRI Preprocessing and Default Network Mapping: Statistical Comparisons with Isotropic/Anisotropic Diffusion
Neuroimaging community usually employs spatial smoothing to denoise magnetic resonance imaging (MRI) data, e.g., Gaussian smoothing kernels. Such an isotropic diffusion (ISD) based smoothing is widely adopted for denoising purpose due to its easy implementation and efficient computation. Beyond these advantages, Gaussian smoothing kernels tend to blur the edges, curvature and texture of images. Researchers have proposed anisotropic diffusion (ASD) and non-local diffusion (NLD) kernels. We recently demonstrated the effect of these new filtering paradigms on preprocessing real degraded MRI images from three individual subjects. Here, to further systematically investigate the effects at a group level, we collected both structural and functional MRI data from 23 participants. We first evaluated the three smoothing strategies' impact on brain extraction, segmentation and registration. Finally, we investigated how they affect subsequent mapping of default network based on resting-state functional MRI (R-fMRI) data. Our findings suggest that NLD-based spatial smoothing maybe more effective and reliable at improving the quality of both MRI data preprocessing and default network mapping. We thus recommend NLD may become a promising method of smoothing structural MRI images of R-fMRI pipeline
Time-Resolved X-Ray Diffraction Investigation of Superheating-Melting of Crystals under Ultrafast Heating
The maximum superheating of a solid prior to melting depends on the effective dimensionless nucleation energy barrier, heterogeneities such as free surfaces and defects, and heating rates. Superheating is rarely achieved with conventional slow heating due to the dominant effect of heterogeneous nucleation. In present work, we investigate the superheating-melting behavior of crystals utilizing ultrafast heating techniques such as exploding wire and laser irradiation, and diagnostics such as time-resolved X-ray diffraction combined with simultaneous measurements on voltage and current (for exploding wire) and particle velocity (for laser irradiation). Experimental designs and preliminary results are presented
Poly[[tetraaquabis(μ3-5-carboxybenzene-1,2,4-tricarboxylato)tricadmium] tetrahydrate]
There are three independent CdII ions in the title complex, {[Cd3(C10H3O8)2(H2O)4]·4H2O}n, one of which is coordinated by four O atoms from three 5-carboxybenzene-1,2,4-tricarboxylate ligands and by two water molecules in a distorted octahedral geometry. The second CdII ion is coordinated by five O atoms from four 5-carboxybenzene-1,2,4-tricarboxylate ligands and by one water molecule also in a distorted octahedral geometry while the third CdII ion is coordinated by five O atoms from three 5-carboxybenzene-1,2,4-tricarboxylate ligands and by one water molecule in a highly distorted octahedral geometry. The 5-carboxybenzene-1,2,4-tricarboxylate ligands bridge the CdII ions, resulting in the formation of a three-dimensional structure. Intra- and intermolecular O—H⋯O hydrogen bonds are present throughout the three-dimensional structure
Plant diversity of Southeast Asia-II
The special issue of plant diversity in Southeast Asia will focus on the documentation of new discoveries in SE Asia. There are four global biodiversity hotspots in Southeast Asia. Although there are many plans to protect this rich biodiversity, however, the rich biodiversity in SE Asia is under threat due to economic development and population growth. There is a huge gap between our knowledge and biodiversity in SE Asia. During the last six investigations, many new taxa, including new species, new genera, have been discovered. This special issue will bring the rich but little known biodiversity to the public and protect them
Diaquabis{1-[(1H-benzimidazol-2-yl)methyl]-1H-imidazole-κN 3}dichloridocadmium hexahydrate
In the title complex, [CdCl2(C11H10N4)2(H2O)2]·6H2O, the CdII atom is located on a twofold rotation axis and is coordinated by two N atoms from two 1-[(1H-benzimidazol-2-yl)methyl]-1H-imidazole ligands and two water O atoms in equatorial positions and by two Cl atoms in axial positions, leading to an elongated octahedral environment. The two coordinating and two of the lattice water molecules are also located on twofold rotation axes. In the crystal, complex molecules and solvent water molecules are linked through a complex intermolecular N—H⋯O, O—H⋯N, O—H⋯O and O—H⋯Cl hydrogen-bonding scheme into a three-dimensional network
(22E,24R)-5α-Ergosta-2,22-dien-6-one
In the title molecule, C28H44O, two six-membered rings have regular chair conformations, while the six-membered ring containing the C=C double bond exhibits a distorted chair conformation. The five-membered ring adopts an envelope conformation. In the crystal, weak intermolecular C—H⋯O interactions link molecules into chains along the b axis. The absolute configuration was assigned to correspond with that of the known chiral centres in a precursor molecule
(22E,24R)-3α,5-Cyclo-5α-ergosta-22-en-6-one
In the title molecule, C28H44O, the two six-membered rings have a chair conformation and the two five-membered rings haveenvelope conformations. The crystal packing exhibits no short intermolecular contacts. The absolute configuration was assigned to correspond with that of the known chiral centres in a precursor molecule, which remained unchanged during the synthesis of the title compound
(E)-N′-(4-Methoxybenzylidene)benzohydrazide
In the title molecule, C15H14N2O2, the dihedral angle between the benzene rings is 5.93 (17)°. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains propagating in [010]
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